<html>
<head>
<title>Pelican preflight wizard</title>
</head>
<body onload="disableNext()">

<h1>Battery</h1>

<hr/>
<form id="checklist">
<ol>
<img src="IMG_1623.JPG" width="600px" />
<li>Using correct AscTec powerpack <input type="checkbox" id="pack" onclick="enableNext()" /></li>
<li>Battery not swolen or damaged <input type="checkbox" id="swell" onclick="enableNext()" /></li>
<img src="IMG_1624.JPG" width="600px" />
<li>Battery checked with 12.0V total or more <input type="checkbox" id="testV" onclick="enableNext()" /></li>
<img src="IMG_1627.JPG" width="600px" />
<li>All cells within 0.1V difference <input type="checkbox" id="cellV" onclick="enableNext()" /></li>
</ol>
</form>
<hr/>

<form id="nav">
<button type = "button" onClick="window.location.href='arena.html'">Previous</button>
<button id="btn_nxt" type = "button" onClick="window.location.href='drone.html'">Next</button>
<button type = "button" onClick="window.location.href='start.html'">Cancel</button>
</form>

<script>
function disableNext() {
    document.getElementById("btn_nxt").disabled = true;
}
</script>

<script>
function enableNext() {
if (document.getElementById("pack").checked) {
if (document.getElementById("swell").checked) {
if (document.getElementById("testV").checked) {
if (document.getElementById("cellV").checked) {
  document.getElementById("btn_nxt").disabled = false;
}
}
}
}
}
</script>

</body>
